Air release valve for self-priming pumps

ABSTRACT

An automatic air release valve for connection to the discharge side of a self-priming pump, which valve includes a through flow passage having a maximum angular flow change of about 45*, a reciprocal valving rod actuatable to open and close the flow passage, a spring urging the rod toward its open position, and a flexible diaphragm connected to the rod and forming an expansible chamber in the housing communicating with the valve inlet so that pressure generated in the chamber will cause the diaphragm to move the rod and close the passage.

United States Patent 1 1 Remy [ 1 Mar. 11, 1975 AIR RELEASE VALVE FORSELF-PRIMING PUMPS [75] Inventor: Dennis K. Remy, Galion, Ohio [73]Assignee: The Gorman-Rupp Company,

Mansfield, Ohio 22 Filed: Mar. 18, 1974 211 Appl. No.: 451,794

[52] U.S. C1 ..417/299,137/505.l3, 137/510 [51} Int. Cl. F04b 49/00,F16k 31/12 158] Field of Search 137/510, 505.13; 417/299; 415/27 [56]References Cited UNITED STATES PATENTS 3,123,094 3/1964 Toschkoff137/505.13

3,575,521 4/1971 Porter 415/21 3,730,215 5/1973 Conery et al. l37/505.l3X

3,732,889 5/1973 Conery et a1. 137/498 Primary ExaminerC. J. HusarAssistant ExaminerRichard E. Gluck Attorney, Agent, or FirmWatts,Hoffmann, Fisher & Heinke Co.

[57] ABSTRACT 15 Claims, 7 Drawing Figures AIR RELEASE VALVE FORSELF-PRIMING PUMPS BACKGROUND OF THE INVENTION The present inventionrelates generally to the selfpriming pump art, and more specifically toa selfpriming pumping system including a new and improved automatic airrelease valve connected to the discharge side of the pump for ventingair from the system.

The customary pumping arrangement employed in sewage lift stations andthe like is comprised of at least one self-priming centrifugal pump, asuction inlet pipe connected to the intake side of the pump, a dischargemain connected to the discharge side of the pump, and a one-way checkvalve in the discharge main which prevents liquid from flowing back tothe pump when it is shut down.

When the pump is started up, the air in the pumping chamber and any airin the section inlet pipe must be evacuated in order to achieve a fullprime. The air which is evacuated cannot be forced pass the check valvein the discharge main because self-priming pumps have limited aircompression capability. For example, a typical four inch self-primingcentrifugal pump may develop a maximum pressure of 7 psi at its ratedspeed. If such a pump is installed in a system with a discharge checkvalve which requires a pressure in excess of 7 psi to open, the pumpwill not develop sufficient pressure to open the check valve andinitiate flow. It is therefore necessary to provide an air release valvebetween the check valve and the pump for venting air from the system. Inorder to have an efficiently operating system, the air release valveshould automatically close when the pump is operating at rated capacityand head.

Various types of air release valves, such as those disclosed in US. Pat.Nos. 3,474,735, 3,575,521, 3,730,215, 3,732,889 and 3,741,675, have beenproposed in the past for use in systems of the type described. Many ofthese prior art valves are unstable under certain operating conditions,for example, low pressure conditions, and are prone to hydraulicchattering. Another serious disadvantage of conventional air releasevalves is that they can be easily plugged or fouled by stones, sticks,stringy material and other solids commonly found in raw sewage and thelike.

SUMMARY or THE INVENTION An object of the present invention is toprovide a pumping system including a self-priming pump and a new andimproved air release valve connected to the discharge side of the pumpwhich is open during the priming cycle to vent the evacuated air andwhich automatically closes when the pump is fully primed to preventventing of liquid during the pumping cycle.

Another object of the present invention is to provide a new and improvedair release valve for use in a pumping system of the type describedwhich is pressure responsive to assure proper opening and closing of thevalving element and which is not subject to hydraulic chattering duringuse.

A further object of the present invention is to provide a new andimproved pressure responsive, air release valve suitable for use inpumping systems handling raw sewage and other liquids which containsolids.

Still another object of the present invention is to provide a new andimproved air release valve of the type described which affords aself-flushing action, whereby any debris in the valve will beautomatically flushed out when the associated pump is actuated.

In the preferred embodiment of the invention, the new air release valvecomprises a housing having a through flow passage which connects inletand outlet ports, a reciprocal valving rod which is movable to open andclose the passage, and a flexible diaphragm which is connected to therod and forms an expansible chamber in the housing. A spring acts on therod to urge it toward an open position of the valve.

An important feature of the new valve construction is that it ispressure responsive rather than flow responsive, as is typical of manyprior art constructions. In the valve of the present invention, theexpanisble chamber on one side of the diaphragm communicates directlywiththe inlet port. When the pressure in this expansible chamberincreases at the end of the priming cycle of the associated pump, thediaphragm is flexed to move the valving rod to a closed position inwhich it plugs the flow passage in the housing. The valve isautomatically opened by the action of the spring whenthe pressure in theexpansible chamber decreases, such as when the pump is shut down and/orwhen the prime is lost. Because of the pressure responsive design of thenew valve construction, it is not subject to hydraulic chattering underlow pressure operating conditions.

Another important feature of the present invention is the constructionwhich avoids clogging by the debris contained in raw sewage, etc. In thepreferred embodiment of the invention, the flow passage through thehousing has a maximum angular flow change, i.e.. maximum deviation fromstraight line flow, of 45. It is also preferred that the flow passagehave a minimum diam eter of one inch. It has been found that a one inchdiameter passage having a maximum angular flow change of 45 avoids allplugging and blockage problems when used to handle raw domestic sewage.

The new valve is preferably installed so that the .expansible chamber inthe valve housing is disposed above the flow passage with which thechamber communicates. Any debris which may find its way into the chamberduring operation of the pump will'settle into the flow passage when thepump has been shut down. The debris will then be automatically flushedout of the valve during the next cycle of the pump.

Other objects, features and advantages of the invention will be had byreference to the following detailed description and the accompanyingdrawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration of asewage lift station embodying the air release valve of the presentinvention;

FIG. 2 is an enlarged top plan view of the new valve;

FIG. 3 is a vertical cross-sectional view taken along the line 3-3 ofFIG. 2;

FIG. 4 is a side elevational view taken along the line 44 of FIG. 3; and1 FIGS. 5, 6 and 7 are cross-sectional views of the valve illustratingdifferent stages of operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,and to FIG. 1 in particular, there is shown a sewage pumping systemwhich includes a conventional self-priming centrifugal pump such asdisclosed in U.S. Pat. No. 3,575,521. In the illustrated arrangement thepump 10 is disposed above a wet wall 11 which collects the sewage to bepumped. A suction inlet line 12 is connected to the intake side of thepump 10 and extends down into the wet wall 11. A discharge main 13 isconnected to the discharge outlet of the pump 10 and extends upwardly.The discharge main 13 is provided with a one-way check valve 14 whichprevents the liquid downstream from the valve from returning to the pump10 when it has been shut down or is not operating at rated capacity andhead.

The pump 10 is driven by an electric motor 15 operated through suitableelectric controls 16.

An air release valve constructed in accordance with the presentinvention is installed in the illustrated pumping system between thepump 10 and the check valve 14 so that the inlet of the valve 20communicates with the discharge outlet of the pump 10 through the main13. An exhaust line 21 is connected to the outlet port of the valve 20and extends into the wet well 13. The purpose of the valve 20 is to ventthe air and liquid which is evacuated from the suction inlet pipe 12 andthe pumping chamber of the pump 10. The valve 20 automatically closeswhen the pump is fully primed to prevent the venting of liquid throughthe valve during the pumping cycle.

Reference is now made to FIGS. 2, 3 and 4 which illustrate the preferredconstruction of. the new air release valve 20. As shown, the valve 20comprises a housing 22 which includes a main body 23 and a cap 24. Thecap 24 is connected to one end of the body 23 by screws 25. The valve 20has an inlet port 26 in the cap 24 adapted to be connected to thedischarge main 13 by an auxiliary pipe 27 and an outlet port 28 in thebody 23 adapted to be connected to theexhaust line 21.

The interior of the housing 22 has a bore 33 which is formed in the endof the body 23 opposite to the cap 24. The bore 33 terminates at theoutlet port 28. A fluid passageway 34 in the body 23 communicates withthe inlet port 26 and has a mouth intersecting the bore 33 near theoutlet port 28. The passageway 34 and a portion of the bore 33 define athrough fluid flow passage connecting the ports 26, 28. In the preferredconstruction of the invention, the flow passage 33, 34 has a minimumdiameter of one inch and a maximum angular flow exchange of 45. Thispreferred construction has been found to avoid all plugging and blockageproblems when the valve is used in pumping systems handling raw domesticsewage.

The valve 20 is opened and closed by movement of a valving rod 35 whichhas one end portion reciprocally disposed in the bore 33. The valvingrod 35 is movable between a closed position as shown in FIG. 6 in whichthe end of the rod blocks the mouth of the passageway 34 and an openposition shown in FIG. 7 in which the end of the rod is withdrawn in thebore 33 so that the mouth of the passageway 34 is uncovered. Thisconstruction in which the rod'35 is withdrawn from the fluid flow pathwhen the valve is open contributes to the clogging-free performance ofthe valve. In some conventional air release valves, the construction issuch that the liquid flows through the valve around the valving elementso that the valve is easily plugged by stringy material and otherdebris.

The valving rod 35 is actuated to its closed position by movement of aflexible diaphragm 36 which is mounted in a cavity formed by the insidesurfaces of the cap 24 and the end of the body 23 to which the cap isconnected. The diaphragm 36 is held in place by clamping its marginaledge between cooperating flanges of the body 23 and the cap 24. Asshown, the valving rod 35 sidably extends through a wall 37 of thehousing body 23 into the cavity in which the diaphragm is mounted. Thecentral part of the diaphragm 36 is clamped between a pair of plates 42,43 which are secured by a nut 44 to a reduced diameter, threaded endportion of the valving rod 35.

The diaphragm 36 cooperates with the inside of the cap 24 to define anexpansible pressure chamber 45. An auxiliary chamber 46 is formed insideof the cap 24 next to the pressure chamber. This auxiliary chamber 46 islocated between the inlet port 26 and the fluid passageway 34 and opensinto one side of the expansible chamber 45 so that fluid entering theinlet port can flow into chamber 45 and generate pressure to flex thediaphragm 36 and move the valving rod 35 to its closed position. Thechamber between the diaphragm 36 and the end of the body 23 is vented tothe atmosphere by a hole 47 extending through the body wall 37.

Access is provided into the expansible pressure chamber 45 by aclean-out opening 48 through the top of the cap 24. The opening 48 isnormally closed by a plate 49 which is secured in place by screws 50.

The valving rod 35 is urged to its open position shown in FIGS. 2, 5 and7 by a spring 52 which surrounds a central portion of the rod. One endof the spring 52 abuts a wall 53 of the housing body 23. The other endof the spring 52 engages an abutment washer 54 which is connected to thevalving rod 35. In the illustrated and preferred embodiment of theinvention, the washer 54 is adjustable along the length of the rod 35toward and away from the wall 53 in order to change the spring loadingof the valve. To this end, the rod 35 is formed with a series of holes55 which are spaced axially of the rod. A pin 56 is adapted to be fittedthrough any one of these holes 55 in order to hold the washer 54 in aselected position.'

When the pump 10 of the system shown in FIG. 1 is shut down, its pumpingchamber. is open to the atmosphere and the valve 20 is held in its openposition due to the fact that the pressure in the valve chamber 45 isinsufficient to overcome the spring 52. Upon the start up of the pump,air from the pumping chamber will be forced out through the open valveas shown in FIG. 5, since the downstream check valve. 14 will be heldclosed by the back pressure of the system head. As the pumpoperationcontinues, liquid will begin to flow with the air until sufficientpressure has been generated in the chamber 45 to overcome the springforce. At that time the pump will have been fully primed and thediaphragm will be forced to the position of FIG. 6 to move the valvingrod 35 to its closed position. Premature closing of the valve can beprevented to assure full prime by proper preload adjustment of thespring assembly 52, 54, 55, 56. Y

Continued operation of the pump 10 causes all of the liquid pumped fromthe wet wall 11 to be forced through the discharge main l3 past-thecheck valve 14. When the pump is next shut down, the pressure in thevalve chamber 45 is relieved so that the valve 20 is automaticallyopened by the spring 52. With the valve open, the system is conditionedfor the next pumping cycle or priming cycle if the suction leg in thepipe 12 drops during the shut down period.

As will be seen from the foregoing description, the valve 20 is pressureresponsive rather than flow responsive due to the large difference inpressure areas between the diaphragm 36 and the end of the valving rod35 in the bore 33. This pressure responsive characteristic of the valve20 is an important feature because it assures full opening and closingmovement of the valving rod and minimized hydraulic chattering.Hydraulic chattering is a common defect of conventional valve designs inwhich a hydraulically balanced condition can occur, especially duringlow pressure operation.

Since the valve 20 is pressure responsive in operation, it can beinstalled in any position. Preferably, however, the valve is installedin a horizontal position as shown in FIGS. 5-7 in order to obtain aself-flushing action when the valve is cycled. In the illustratedposition, the expansible pressure chamber 45 of the valve 20 is abovethe auxiliary chamber 46. Any debris which finds its way into the valvewhile it is closed as shown in FlG. 6 will remain suspended in thechamber 45 and- /or will be held in the passageway 34 and the chamber 46until the pump is shut down. When the pump is shut down and the valveopens as shown in FIG. 7, the movement of the diaphragm will force anydebris out of the chamber 45 into the chamber 46 and the debris will becompletely flushed out of the valve the next time the pump is started.lt will thus be seen that the invention achieves the objective ofproviding a reliable valve capable of being used in pumping systemshandling raw sewage with contained solids.

Many variations and modifications of the invention will be apparent tothose skilled in the art in view of the foregoing detailed disclosure.Therefore, it is to be understood that, within the scope of the appendedclaims, the invention can be practiced otherwise than as specificallyshown and described.

What is claimed is:

1.1n a pumping system including a self-priming pump having an inlet andan outlet, a check valve downstream from said outlet, and an air releasevalve operatively arranged between said outlet and said check valve forpermitting the flow of fluid therethrough when said check valve isclosed, the improvement wherein said air release valve comprises:

a. a housing having an inlet port connected to said pump outlet, anoutlet port communicating to exhaust, and a flow passage extendingbetween said ports,

b. a valving plug reciprocally mounted in said housing for pressureresponsive movement between a closed position in which an end portion ofsaid plug extends into and blocks said flow passage and an open positionin which said end portion of said plug is withdrawn from said passage soas to permit unobstructed flow, and

c. actuating means for causing movement of said plug between saidpositions,

d. said actuating means including movable means mounted in said housingto define an expansible chamber communicating with one of said ports,

e. said movable means being connected to said plug at a location remotefrom said passage and said one end portion and being movable by pressuregenerated in said chamber to move said plug to one of said positions.

2. The improvement as claimed in claim 1 in which said chamber isdisposed above said flow passage so that debris in said chamber willsettle into said flow passage and be flushed from said valve when it isopened and said pump is actuated.

3. The improvement as claimed in claim 1 in which the maximum angularflow change of said passage is 45.

4. The improvement as claimed in claim 1 in which said housing has aclean-out opening into said chamber and includes a removable cover forsaid opening.

5. In a pumping system including a self-priming pump having an inlet andan outlet, a check valve downstream from said outlet, and an air releasevalve operatively arranged between said outlet and said check valve forpermitting the flow of fluid therethrough when said check valve isclosed, the improvement wherein said air release valve comprises:

a. a housing having inlet and outlet ports and a through flow passageconnecting said ports,

b. a valving rod reciprocally mounted in said housing for movementbetween a closed position in which one end of said rod blocks saidpassage and an open position in which said end portion of said rod iswithdrawn from said passage so as to permit unobstructed flow,

0. a diaphragm mounted in said housing to define:

i. an expansible pressure chamber on one side of the said diaphragmhaving an opening in communication with said inlet port and saidpassage,

ii. a chamber on the other side of said diaphragm which is vented to theatmosphere,

d. means connecting said diaphragm to said rod so that the pressuregenerated in said expansible chamber will cause said diaphragm to movesaid rod to one of said positions, and

e. biasing means resiliently urging said rod to the other of saidpositions.

6. The improvement as claimed in claim 5 in which said expansiblechamber is disposed above said flow passage so that debris in saidexpansible chamber will settle into said flow passage and be flushedfrom said valve when it is opened and said pump is actuated.

7. In a pumping system including a self-priming pump having an inlet andan outlet, a check valve downstream from said outlet, and an air releasevalve operatively arranged between said outlet and said check valve forpermitting the flow of fluid therethrough when said check valve isclosed, the improvement wherein said air release valve comprises:

a. a housing having inlet and outlet ports, a bore terminating at saidoutlet port, and a fluid passageway extending from said inlet port to amouth intersecting said bore,

b. a valving rod reciprocally mounted in said bore for movement betweena closed position in which one end of said rod blocks the mouth of saidpassageway and an open position in which the mouth of said passageway isuncovered so as to permit unobstructed flow,

c. a diaphragm mounted in said housing to define:

i. an expansible pressure chamber on one side of said diaphragm having aside opening in commu nication with said inlet port and said passageway,

ii. another chamber on the other side of said diaphragm which is ventedto the atmosphere,

d. said valve being positioned so that said expansible chamber isdisposed above said passageway, whereby debris in said expansiblechamber entering from said inlet port will settle into said flow passageand be flushed from said valve when it is opened and said pump isactuated,

e. means connecting said diaphragm to said rod so that pressuregenerated in said expansible chamber will cause said diaphragm to movesaid rod to said closed position of said valve, and

f. means resiliently urging said rod to said open position of saidvalve.

8. The improvement as claimed in claim 7 wherein said passageway and aportion of said bore cooperate to define a through fluid flow passagehaving a maximum angular flow change of about 45.

9. The improvement as claimed inclaim 8 wherein said fluid flow passagehas a minimum diameter of about 1 inch.

10. A pressure responsive flow control valve comprising:

a. a housing having first and second ports and a through flow passageconnecting said ports,

b. a valve plug reciprocally mounted in said housing for movementbetween a closed position in which a portion of said plug extends intoand blocks said passage and an open position in which said plug iswithdrawn from said passage so as to permit unobstructed flow, and

c. acutating means for causing movement of said plug between saidpositions,

d. said actuating means including movable means mounted in said housingto define an expansible chamber communicating with one of said ports,

e. said movable means being connected to said plug at a location spacedfrom said passage andbeing movable by pressure generated in said chamberto move said plug to one of said positions.

1]. A pressure responsive flow control valve comprising:

a. a housing having inlet and outlet ports and a through flow passageconnecting said ports,

b. a valving plug reciprocally mounted in said housing for pressureresponsive movement between a closed position in which a portion of saidplug extends into and blocks said passage and an open position in whichsaid portion of said plug is withdrawn from said passage so as to permitunobstructed flow, and

c. actuating means for causing movement of said plug between saidpositions,

d. said actuating means including a flexible diaphragm mounted in saidhousing to define:

i. an expansible pressure chamber on one side of said diaphragm having aside opening communicating with said passage and said inlet port,

ii. another chamber on the other side of said diaphragm which is ventedto the atmosphere,

e. said diaphragm being connected to said plug and being movable bypressure generated in said expansible chamber to move said plug to oneof said positions.

12. The valve as claimed in claim 11 in which said passage has a maximumangular flow change of about 45.

13. A pressure responsive flow control valve comprising:

a. a housing having inlet and outlet ports, a bore terminating at saidoutlet port, and a fluid passageway extending from said inlet port to amouth intersecting said bore,

b. a valving rod reciprocally mounted in said bore for movement betweena closed position in which a portion of said rod blocks the mouth ofsaid passageway and an open position in which the mouth of saidpassageway is uncovered so as to permit unobstructed flow,

c. a diaphragm mounted in said housing to define:

i. an expansible pressure chamber having a side opening in communicationwith said passageway in said inlet port,

ii. another chamber on the other side of said diaphragm which is ventedto the atmosphere,

d. means connecting said diaphragm to said rod so that pressuregenerated in said expansible chamber will cause said diaphragm to movesaid rod to said closed position, and

e. biasing means resiliently urging said rod to said open position. I

14. A valve as claimed in claim 13 wherein said passageway and a portionof said bore cooperate to define a through fluid flow passage having'amaximum angular flow change of about 45.

15. A valve as claimed in claim 13 in which said housing has a clean-outopening providing access into said expansible chamber, and a removablecover for said clean-out opening.

1. In a pumping system including a self-priming pump having an inlet andan outlet, a check valve downstream from said outlet, and an air releasevalve operatively arranged between said outlet and said check valve forpermitting the flow of fluid therethrough when said check valve isclosed, the improvement wherein said air release valve comprises: a. ahousing having an inlet port connected to said pump outlet, an outletport communicating to exhaust, and a flow passage extending between saidports, b. a valving plug reciprocally mounted in said housing forpressure responsive movement between a closed position in which an endportion of said plug extends into and blocks said flow passage and anopen position in which said end portion of said plug is withdrawn fromsaid passage so as to permit unobstructed flow, and c. actuating meansfor causing movement of said plug between said positions, d. saidactuating means including movable means mounted in said housing todefine an expansible chamber communicating with one of said ports, e.said movable means being connected to said plug at a location remotefrom said passage and said one end portion and being movable by pressuregenerated in said chamber to move said plug to one of said positions. 1.In a pumping system including a self-priming pump having an inlet and anoutlet, a check valve downstream from said outlet, and an air releasevalve operatively arranged between said outlet and said check valve forpermitting the flow of fluid therethrough when said check valve isclosed, the improvement wherein said air release valve comprises: a. ahousing having an inlet port connected to said pump outlet, an outletport communicating to exhaust, and a flow passage extending between saidports, b. a valving plug reciprocally mounted in said housing forpressure responsive movement between a closed position in which an endportion of said plug extends into and blocks said flow passage and anopen position in which said end portion of said plug is withdrawn fromsaid passage so as to permit unobstructed flow, and c. actuating meansfor causing movement of said plug between said positions, d. saidactuating means including movable means mounted in said housing todefine an expansible chamber communicating with one of said ports, e.said movable means being connected to said plug at a location remotefrom said passage and said one end portion and being movable by pressuregenerated in said chamber to move said plug to one of said positions. 2.The improvement as claimed in claim 1 in which said chamber is disposedabove said flow passage so that debris in said chamber will settle intosaid flow passage and be flushed from said valve when it is opened andsaid pump is actuated.
 3. The improvement as claimed in claim 1 in whichthe maximum angular flow change of said passage is 45*.
 4. Theimprovement as claimed in claim 1 in which said housing has a clean-outopening into said chamber and includes a removable cover for saidopening.
 5. In a pumping system including a self-priming pump having aninlet and an outlet, a check valve downstream from said outlet, and anair release valve operatively arranged between said outlet and saidcheck valve for permitting the flow of fluid therethrough when saidcheck valve is closed, the improvement wherein said air release valvecomprises: a. a housing having inlet and outlet ports and a through flowpassage connecting said ports, b. a valving rod reciprocally mounted insaid housing for movement between a closed position in which one end ofsaid rod blocks said passage and an open position in which said endportion of said rod is withdrawn from said passage so as to permitunobstructed flow, c. a diaphragm mounted in said housing to define: i.an expansible pressure chamber on one side of the said diaphragm havingan opening in communication with said inlet port and said passage, ii. achamber on the other side of said diaphragm which is vented to theatmosphere, d. means connecting said diaphragm to said rod so that thepressure generated in said expansible chamber will cause said diaphragmto move said rod to one of said positions, and e. biasing meansresiliently urging said rod to the other of said positions.
 6. Theimprovement as claimed in claim 5 in which said expansible chamber isdisposed above said flow passage so that debris in said expansiblechamber will settle into said flow passage and be flushed from saidvalve when it is opened and said pump is actuated.
 7. In a pumpingsystem including a self-priming pump having an inlet and an outlet, acheck valve downstream from said outlet, and an air release valveoperatively arranged between said outlet and said check valve forpermitting the flow of fluid therethrough when said check valve isclosed, the improvement wherein said air release valve comprises: a. ahousing having inlet and outlet ports, a bore terminating at said outletport, and a fluid passageway extending from said inlet port to a mouthintersecting said bore, b. a valving rod reciprocally mounted in saidbore for movement between a closed position in which one end of said rodblocks the mouth of said passageway and an open position in which themouth of said passageway is uncovered so as to permit unobstructed flow,c. a diaphragm mounted in said housing to define: i. an expansiblepressure chamber on one side of said diaphragm having a side opening incommunication with said inlet port and said passageway, ii. anotherchamber on the other side of said diaphragm which is vented to theatmosphere, d. said valve being positioned so that said expansiblechamber is disposed above said passageway, whereby debris in saidexpansible chamber entering from said inlet port will settle into saidflow passage and be flushed from said valve when it is opened and saidpump is actuated, e. means connecting said diaphragm to said rod so thatpressure generated in said expansible chamber will cause said diaphragmto move said rod to said closed position of said valve, and f. meansresiliently urging said rod to said open position of said valve.
 8. Theimprovement as claimed in claim 7 wherein said passageway and a portionof said bore cooperate to define a through fluid flow passage having amaximum angular flow change of about 45*.
 9. The improvement as claimedin claim 8 wherein said fluid flow passage has a minimum diameter ofabout 1 inch.
 10. A pressure responsive flow control valve comprising:a. a housing having first and second ports and a through flow passageconnecting said ports, b. a valve plug reciprocally mounted in saidhousing for movement between a closed position in which a portion ofsaid plug extends into and blocks said passage and an open position inwhich said plug is withdrawn from said passage so as to permitunobstructed flow, and c. actuating means for causing movement of saidplug between said positions, d. said actuating means including movablemeans mounted in said housing to define an expansible chambercommunicating with one of said ports, e. said movable means beingconnected to said plug at a location spaced from said passage and beingmovable by pressure generated in said chamber to move said plug to oneof said positions.
 11. A pressure responsive flow control valvecomprising: a. a housing having inlet and outlet ports and a throughflow passage connecting said ports, b. a valving plug reciprocallymounted in said housing for pressure responsive movement between aclosed position in which a portion of said plug extends into and blockssaid passage and an open position in which said portion of said plug iswithdrawn from said passage so as to permit unobstructed flow, and c.actuating means for causing movement of said plug between saidpositions, d. said actuating means including a flexible diaphragmmounted in said housing to define: i. an expansible pressure chamber onone side of said diaphragm having a side opening communicating with saidpassage and said inlet port, ii. another chamber on the other side ofsaid diaphragm which is vented to the atmosphere, e. said diaphragmbeing connected to said plug and being movable by pressure generated insaid expansible chamber to move said plug to one of said positions. 12.The valve as claimed in claim 11 in which said passage has a maximumangular flow change of about 45*.
 13. A pressure responsive flow controlvalve comprising: a. a housing having inlet and outlet ports, a boretermiNating at said outlet port, and a fluid passageway extending fromsaid inlet port to a mouth intersecting said bore, b. a valving rodreciprocally mounted in said bore for movement between a closed positionin which a portion of said rod blocks the mouth of said passageway andan open position in which the mouth of said passageway is uncovered soas to permit unobstructed flow, c. a diaphragm mounted in said housingto define: i. an expansible pressure chamber having a side opening incommunication with said passageway in said inlet port, ii. anotherchamber on the other side of said diaphragm which is vented to theatmosphere, d. means connecting said diaphragm to said rod so thatpressure generated in said expansible chamber will cause said diaphragmto move said rod to said closed position, and e. biasing meansresiliently urging said rod to said open position.
 14. A valve asclaimed in claim 13 wherein said passageway and a portion of said borecooperate to define a through fluid flow passage having a maximumangular flow change of about 45*.